Vacuum pumping and abatement systems are known hereto for evacuating processing gas from a process chamber and removing noxious substances from the processing gas. Such a system comprises a vacuum pump for evacuating processing gas from a process chamber; and a burner for receiving processing gas from the vacuum pump and removing noxious substances therefrom by burning the processing gas in a fuel and oxygen mixture which is introduced to the burner downstream of the vacuum pump.
Some of processing gases evacuated by the vacuum pump may be corrosive, particularly in the presence of moisture. Corrosion of the pump must be avoided because otherwise it decreases the lifetime of the pump or results in pump failure. In known systems, dry nitrogen is used to purge the pump and dilute the potentially corrosive gases. Nitrogen is used as it does not typically react with the corrosive gases.
This known system suffers from the disadvantage that nitrogen and oxygen must be bought by the operator of the system adding to the cost of ownership and operation. Additionally, pure nitrogen and oxygen must be generated separately using cryogenic distillation requiring energy, therefore contributing to an increased carbon footprint. Thirdly adding oxygen to a fixed flow of nitrogen purge gas results in an elevated total gas flow; as fuel usage in the burner is proportional to total gas flow this results in higher fuel usage.